diff --git a/src/Ratchet/Session/Serialize/PhpHandler.php b/src/Ratchet/Session/Serialize/PhpHandler.php
index 8fb5308..b1df356 100644
--- a/src/Ratchet/Session/Serialize/PhpHandler.php
+++ b/src/Ratchet/Session/Serialize/PhpHandler.php
@@ -3,10 +3,21 @@ namespace Ratchet\Session\Serialize;
 
 class PhpHandler implements HandlerInterface {
     /**
+     * Simply reverse behaviour of unserialize method.
      * {@inheritdoc}
      */
     function serialize(array $data) {
-        throw new \RuntimeException("Serialize PhpHandler:serialize code not written yet, write me!");
+        $preSerialized = array();
+        $serialized = '';
+
+        if (count($data)) {
+            foreach ($data as $bucket => $bucketData) {
+                $preSerialized[] = $bucket . '|' . serialize($bucketData);
+            }
+            $serialized = implode('', $preSerialized);
+        }
+
+        return $serialized;
     }
 
     /**
diff --git a/tests/unit/Session/Serialize/PhpHandlerTest.php b/tests/unit/Session/Serialize/PhpHandlerTest.php
index 4dddee9..4acf5bc 100644
--- a/tests/unit/Session/Serialize/PhpHandlerTest.php
+++ b/tests/unit/Session/Serialize/PhpHandlerTest.php
@@ -33,4 +33,11 @@ class PhpHandlerTest extends \PHPUnit_Framework_TestCase {
     public function testUnserialize($in, $expected) {
         $this->assertEquals($expected, $this->_handler->unserialize($in));
     }
+
+    /**
+     * @dataProvider serializedProvider
+     */
+    public function testSerialize($serialized, $original) {
+        $this->assertEquals($serialized, $this->_handler->serialize($original));
+    }
 }